The field of the invention is systems and methods for computed tomography (“CT”) imaging. More particularly, the invention relates to systems and methods for controlling both radiation dose and intravenous (“IV”) contrast agent dose.
Despite tremendous effort in the CT community to minimize radiation dose, scanning protocols and radiation doses still vary widely among different CT practices, which poses substantial risks to patient safety. The substantial variation in protocols and radiation dose is largely attributable to the lack of an efficient and widely available approach to optimizing CT protocols.
Clinical evaluation by interpreting physicians is the most commonly used approach to determining the lowest possible radiation dose in CT protocols. To do the evaluation, one can gradually decrease the scanning technique until the image quality approaches the minimum acceptable limit. This approach requires exploratory low-dose scans on a number of patients, which is tedious and can potentially result in diagnostically compromised image. A more elegant approach is to use a noise insertion tool to simulate images at reduced dose levels from “standard dose” existing exams. A range of simulated dose levels can be generated and the diagnostic quality comparisons can be done across the same patient, removing patient-specific variables. This approach enables radiologists to determine the lowest acceptable dose level without risk of compromising a patient scan, which has been used for optimizing CT scanning protocols. Due to the proprietary nature of the CT raw data, the noise-insertion tools for clinical use have often been developed by manufacturers and distributed to very few users under research agreement. The technical details of the tools are not publicly available and the accuracy is usually out of the users' control, which makes their applications rather limited.
Even assuming that a reduced dose is appropriately selected by a clinician, the clinical value of the image may be correspondingly reduced by the introduction of additional variables to the imaging process. For example, the use of an intravenous (IV) contrast agent or the introduction of additional noise to the imaging process can drastically change the dose requirements.
Therefore, it would be desirable to have a system and method for managing the variables and interplay between selecting a desired radiation and IV contrast agent dose, while controlling against the risk of providing images that may not meet clinical needs because the dose of radiation or IV contrast agent is too low.